Integrated circuit (IC) fabrication processes include anneal operations to perform various functions, including activation of dopants and reduction of crystal lattice damage from ion implantation. Laser scan annealing, which involves irradiating a small region of an IC surface with light from a laser while scanning the irradiated region over the whole surface of the IC substrate, typically a wafer, is an annealing technique that has advantages over other annealing techniques, such as rapid thermal annealing or furnace annealing. Laser scan annealing is being used more frequently on ICs with structures smaller than 100 nanometers.
Defect mechanisms unique to laser scan annealing have been observed. One mechanism is degradation of gate oxide integrity in large polysilicon capacitors.